Diseased leaf?

I have 3 plants and 2 of them are showing a some yellowing here and there, which I'm not too concerned about. I'm also fending off a pest of some kind with insecticidal soap, which has limited the damage so far.

But this leaf looked unusual to me, so I pruned it. Any idea what's happening to it? Is pruning potentially diseased leaves a good policy?

I'm a first time hops grower myself, and some of my hops are showing similar symptoms. Based on this freshhops.com posting, it would look like it's probably nitrogen deficiency ("brown spots develop interveinally"). Looks like we need to fertilize, but I could be wrong...

I'm having also having a problem with my Hallertauer leaves turning white. Living in Texas, I doubt I'm overwatering, but it may very well be that. If you've got any ideas, I'd love to hear 'em.